The serious cardiological diseases include the tachycardial arrhythmias, such as atrial fibrillation for example. In this situation, the vestibule is very frequently excited by conduction disturbances in the heart. In the case of other, for example ventricular, tachycardias the result is a complete contraction and thus an inadequate pumping performance by the heart. In the past, an attempt was made either to reduce the effect of the atrial fibrillation by means of a continuous intake of medicines or to eliminate the cause of the atrial fibrillation by means of a heart operation in which the conduction tissue is severed in certain parts of the vestibule. This surgical treatment does however have a relatively high risk for the patient. A minimally invasive therapy method has been establishing itself in recent times. In this situation, an ablation catheter is inserted into the vestibule with access through a vein. The ablation catheter then allows the disruptive conduction paths to be severed using electrical energy, high-frequency radiation for example. In this minimally invasive therapy, the disruptive conduction paths must be obvious to the doctor treating the condition in order that they can be correctly targeted by the ablation catheter. To this end, as a rule a mapping catheter is inserted with which the electrophysiological potentials in the heart are recorded with local resolution prior to the therapy and displayed on a monitor.
The minimally invasive diagnosis and therapy of tachycardial arrhythmias is carried out in an electrophysiological laboratory in which an angiographic X-ray unit, a device for recording an intracardiac ECG, a mapping catheter and also the ablation catheter are available. The method itself is generally referred to in electrophysiology as high-frequency ablation or RF ablation. The method for measuring the electrophysiological potentials in the heart in order to determine the ablation location in each case with the mapping catheter is referred to as mapping.
A method and a device for supporting the diagnosis and RF ablation and also the mapping are known from U.S. Pat. No. 6,556,695 B1, which provide the user with an enhanced navigation capability during the actual ablation procedure. With regard to the method, before the procedure commences 3D images of the heart are produced by means of a 3D imaging arrangement, in particular a computer tomograph or a magnetic resonance tomograph. These 3D images are registered using the coordinate system of the mapping catheters such that the 3D images can be displayed superimposed together with the mapping data. During the execution of the procedure, 2D images are additionally recorded using an intracardiac ultrasound catheter and are likewise superimposed on the displayed image data in order to provide the medical user with updated information for orientation and navigation purposes during the procedure. Use of this technique does however require that 3D images be recorded in a different station before the procedure since as a rule no computer tomograph or magnetic resonance tomograph is available in an electrophysiological laboratory. This means an increased time requirement for patient and hospital personnel.